TECH-SAVVY Singaporeans are keen about buying the latest anti-virus software for their computers, but a lot less so about protecting themselves while surfing the Internet, say information technology security specialists.

Consultants from IT security firms Sophos and Symantec point out that openly volunteering personal details such as contact numbers, home addresses and dates of birth can put one at risk of harassment, identity theft, fraud and phishing.

A recent survey by Symantec confirmed online users' cavalier attitudes: Half of the 130 Nanyang Technological University students polled said they have posted sensitive personal data on their social networking profiles, and one in three has accepted friendship requests from strangers.

The social networks were not specified, but popular ones among Singapore Internet users include Facebook, Friendster and MySpace.

Some online users say they are wary. Polytechnic student Jamie Lee, 19, who is on three social networking sites, said she has been alerted to the dangers following some incidents, the most serious of which involved a stranger who turned up at a friend's home, going by the home address she posted on her profile.

She and her friends have also received prank calls and had men making passes at them. She remains on her guard - even as she puts herself on new social networks.

Among 50 older online users polled separately, a disturbing 60 per cent said they had no qualms about receiving strangers into their circle of friends or revealing where they worked.

For sales executive Louis Lye, 37, and Mr Eugene Tay, 29, who runs workshops for children, the perks of reaching customers and long-lost friends through networks like Facebook are too attractive to pass up.

Mr Lye, who leaves his mobile number on his Facebook profile, said: 'I think I'm discerning enough to tell if someone is trying to con me using my personal information.'

Mr Tay, who is registered on five social networks and puts his contact numbers, home address and workplace on these sites, said: 'I don't see the bad things, I only see the benefits. Long-lost friends, neighbours and even future customers can easily get me if they want to.'

Mention the dangers and his response is that he will 'deal with them when the time comes'.

Singaporeans, it appears, are not the only ones being so naively open online. In a global 'test' Sophos ran on 200 Facebook users, 41 per cent broadcast their e-mail addresses, dates of birth and phone numbers to a fake persona that the IT security firm set up on Facebook.

Mr Paul Ducklin, Sophos Asia-Pacific's head of technology, noting that people may not see the danger in publicising their date of birth, pointed out that banks, for example, still use date of birth to verify the identity of an individual who calls to seek assistance.

Someone who knows your birth date can therefore masquerade as you and change the delivery address for your new credit card, he said.

He also advised users against blabbing too much about their workplace, especially those who add strangers to their list of friends.

The 'friends' you see as knowledgeable insiders could be hackers who can 'trick you into believing they really are from IT, or that they really do need to know your password'.

Mr Gavin Lowth, the director of online channels at Symantec, said users of social networking sites may also compromise their 'real' friends' security, because cyber attacks can spread rapidly through one's social circle.

Mr Ducklin added: 'We don't know how social networks are going to end up, legally or tech-wise. So if your current thought is that you are trusting the world till something goes wrong, you might want to turn that thought the other way around.'

tanwz@sph.com.sg